The invention is based on an electrical component according to the general description of the primary claim. It is known that electrical components can be identified using applied bar codes and/or type descriptions. To process this information further using an electrical device, however, the type of electrical component must also be entered manually. In computer technology, moreover, it is known that information about the identity of computer components can be queried via an interface. A fuel supply system in the form of a pump is made known in U.S. Pat. No. 4,487,181, in which the data from the pump are recorded on the pump housing during a test phase. This test recording is carried out in the form of a resistor network, with the values of the resistors representing information about the data from the pump during the test phase. Transmission to a control system is made possible by way of a cable connection.
In contrast, the electrical component according to the invention has the advantage that information about the identity of the electrical component is collected by measuring a voltage at a voltage divider, which is part of a resistor network in the electrical component. This is particularly advantageous because the divided voltage that can be drawn from the voltage divider is independent of the absolute values of the resistors in the resistor network and only depends on the ratio of the resistors in the voltage divider. In particular, a temperature dependence of the resistors is eliminated in the voltage measurement, and it can therefore no longer lead to mistaken identification of the electrical component. A further advantage is the fact that a voltage measurement can be carried out using a measuring device having a very high internal resistance. The measurement can therefore be carried out using very low currents.
Furthermore, it is advantageous to design the resistor network as a multitude of parallel circuits of series circuits of two-ohm resistors, and to tap a voltage between each of the two resistors connected in series and to measure it against a fixed reference potential. Since the number of potential voltage values is unlimited due to the tolerances of the resistors and a limited resolution of the measuring device, the scope of the storable information used to identify the electrical component can be increased by using an arrangement of a multitude of series circuits. It is also advantageous that the values of the resistors in the resistor network are selected in graduations, so that, at the specified reference voltage, only voltage values can be measured up to the reference voltage, the tolerance ranges of each of which is disjoint. This makes it possible to unequivocally assign a measured voltage value to a theoretical voltage value that is used to subsequently identify the electrical component.
It is also advantageous that the electrical component has an input for a reference voltage. As a result, a measuring device does not depend on a supply voltage of the electrical component. This is sensible in particular when the electrical component has not yet been activated at the time of identification and is therefore not yet supplied with operating voltage. Moreover, the voltage applied to the electrical component may fluctuate, so that a measurement could possibly lead to incorrect identification. If the reference voltage is applied to the electrical component from the outside, this voltage can be checked directly using a measuring unit.
It is also advantageous to provide a method for identifying the electrical component, by means of which the voltage is measured at at least one resistor of the voltage divider, and information is determined by the evaluation unit that makes it possible to identify the electrical component. The measured voltage is hereby converted into a signal that can be processed further.
It is also advantageous to convert the measured voltage to a digital code using an analog-digital converter. This eliminates measuring errors that occur as a result of resistor tolerances or voltage drop at the supply leads, as well as inaccuracy of the measuring device. Moreover, a digital code makes further processing by way of a central processor possible.
It is also advantageous to use direct voltage as the reference voltage, because, unlike with alternating voltage, the resistor values are not frequency-dependent with direct voltage, as with capacitive or inductive loads.
It is also advantageous that the digital code of the analog-digital converter is fed further to a central processor that compares the digital code with stored digital codes and, if the code determined matches a stored digital code, the type of device can be called up from the memory unit and transmitted to an output unit or a data output. The device can therefore be identified even in the evaluation unit, so that a type of device can be displayed at the output unit or transmitted to a further central processor.
It is also advantageous that the digital code is fed further from the evaluation unit directly to a second central processor, whereby the device is identified directly by the evaluation unit or the second central processor with access to a second memory unit. It is advantageous thereby that data for the operation of the electrical device can be loaded from the second memory unit by way of the second central processor. A situation in which the user must manually select the electrical component that is present or insert a special data carrier into the second memory unit that only carries data for the operation of the electrical component is thereby prevented. Moreover, only one medium for a line of products in which different variants of electrical components are used, only one medium for the memory unit need be created.
It is advantageous thereby that, depending on the identification of the electrical component, the data required to operate the electrical component are automatically loaded in the second memory unit, if one is available.
It is also advantageous to provide an evaluation unit having an analog-digital converter that converts the voltages measured at the electrical component into a digital code, because they can be processed further by a central processor. It is also advantageous to provide the evaluation unit with a central processor and a memory unit by means of which the digital code can be assigned to a type of device stored previously in the memory unit; because the type of device can then be displayed directly by the evaluation unit, or it can be transmitted to a further central processor, for example.